Increasingly there is scientific insight that early, presymptomatic intervention can emphatically change the biological behaviour of the most important life-threatening disease processes, such as atherosclerosis and many types of cancer.1-6 Our current healthcare system is as yet mainly fixated on the occurrence of symptoms. However, from the standpoint of the medical process symptoms are no more than a first sign of underlying disease processes that have existed for years and sometimes even throughout the patient's life. In fact, symptoms arise only very late in the natural course of the abovementioned and other disease processes. There is often then already irreversible organ damage (vascular diseases) or metastasisation that can no longer be cured.
This is further illustrated in FIG. 1, which shows the development of cancer as a disease process. FIG. 1 shows that in a first stage abnormal cells arise, whilst in subsequent stages there will be hyperplasia, dysplasia, a local tumour and a metastasised tumour, respectively. Prevention is still possible at the stages of abnormal cells and hyperplasia, early diagnostics can be carried out at the dysplasia stage, early intervention can take place at the stage of a local tumour and a late intervention can possibly still take place at the metastasised tumour stage.
In practice, therefore, waiting for symptoms often means too late a starting point for effective treatment. The high morbidity that is the consequence of this is associated with high costs and complex treatment. Despite the fact that there is progress in the development of new and more effective treatments and advances are still being made, the costs per year of life gained are high if these treatments are employed only at the end of the disease process. In this context there will, by definition, increasingly be a “reduced marginal return”, which ultimately makes a broad-based social discussion on the rationalisation of care offered in the final stage of disease processes unavoidable.
If care is to have a healthy future there will have to be a gradual, but emphatic, shift from “care of the sick” to “healthcare” in the most literal sense. This shift in medical focus is made possible by the rapidly increasing insight into the biology of diseases/disease processes and impressive developments in the field of (early) diagnostics related to this. This progress will increasingly underline the importance of prevention and early intervention.
In many cases symptoms arise only when the tumour impedes the organ function or grows in blood vessels. By definition, the risk of metastasisation, which it may or may not be possible to diagnose, is then high. The representation in FIG. 1 shows disease as a process and illustrates the possibilities for an earlier influence on this. The “atherosclerosis” disease process can be illustrated in a virtually identical manner.
Healthcare in The Netherlands (and beyond) is under severe pressure. Costs continue to rise exponentially, whilst the peak in the aging population has not yet been reached. In 2003 The Netherlands spent almost 10% of the gross national product on healthcare (44 billion Euros).7-11 A significant proportion of this growing expenditure is accounted for by the treatment of life-threatening complaints such as cancer and heart and vascular diseases, which together account for 60-70% of deaths in the Dutch/Western population.
Healthy life expectancy is approximately the same for men as for women: 61.3 and 60.8 years, respectively. In view of the life expectancy of 75.5 years for men and of 80.6 years for women, this means that women on average live in relative ill health for almost 20 years and men for approximately 14 years. On average, for both men and women, the first symptoms of underlying disease processes start from the age of 50.
FIGS. 2a and 2b show survival curves for men and women, respectively, in 2000. The surface area between the lines represents, from bottom to top, the number of years in good health and in slight, moderate and serious ill health (sources: CBS (Central Bureau voor de Statistiek (Central Office for Statistics) Statistics on causes of death). Life-threatening disease processes can be established at an early (presymptomatic) stage using advanced diagnostic techniques. There are also increasing scientific indications that prevention and/or early (presymptomatic) intervention can emphatically change the biological behaviour of these processes. Therefore, if employed in the correct manner and in the correct disease processes, adequate and early intervention in good time could itself lead, with simple means, to an appreciable gain in health and thus to an increase in (healthy) life expectancy. In theory the “socially active years” can increase significantly and the costs per year of life gained are relatively low, both at the individual and at population level.7 
An appreciable proportion of the morbidity and mortality in the western world is associated with our lifestyle. At the individual level on average 70-80% of the total medical costs are incurred in the last 5 years of someone's life with a peak in the last year of life. Whilst the total costs of healthcare in 2004 were approximately 44 billion per year, less than 2 billion (<4%) were spent on prevention. This sum includes, inter alia, the vaccination programmes for the prevention of infectious diseases, so that only a small proportion of this sum is available for the prevention of/early diagnostics for heart and vascular diseases and cancer.7, 8, 11 There is still a great deal to be gained by adequate and cost-effective implementation of early intervention and more preventive measures, both for the individual patient and for the population and for the costs of healthcare in general.7 
In this context it is extremely valuable that the developments in the diagnostic field in particular have been very rapid in recent years. Unravelling the genetic and molecular backgrounds of diseases has yielded techniques which, on the one hand, can reveal an increased risk of the development of a specific disorder and, on the other hand, can establish early manifestations even before there are symptoms or complaints. Even in the field of instrumental imaging techniques, increasingly more sophisticated techniques are becoming available which have improved sensitivity and resolution compared with the conventional techniques. The possibilities for detecting early, presymptomatic signals of a wide variety of diseases, in the form of genetic, molecular and/or incipient anatomical abnormalities, are emphatically improved as a result.1, 2, 6, 12 The end of these developments is still a long way off, on the contrary.
Despite the above, there is justifiable hesitation in seeking wider implementation of the conventional preventive “screening model”. The current inefficient and expensive logistics for separate screening programmes, combined with scientifically founded drawbacks of conventional screening (overdiagnosis and treatment, high costs, inexpensive but out-of-date and less sensitive techniques, organisational dilemmas, etc.) are all reasons for reticence.
Therefore there is a need for a system with which clients can be screened for diseases that are latent or actually present that does not have the above mentioned disadvantages.